Luminescent reaction measurement device

ABSTRACT

Light resulting from chemiluminescence inside a reaction chamber  4  is transmitted through a light transmitting window  3 , a large part of the light is made incident on a photoelectric surface  71  of a photomultiplier tube  2  to generate photoelectrons, and these photoelectrons are successively multiplied by surfaces  79  at one side of dynodes  78   a   , 78 , and  78   b . Meanwhile, a part of the light that is not made incident on photoelectric surface  71  is made incident on and reflected by a surface  77  at the other side of dynode  78   a , returned to reaction chamber  4  via light transmitting window  3 , reflected further by light reflecting surfaces  40  and  41  inside reaction chamber  4 , emitted again from light transmitting window  3 , and made incident on photoelectric surface  71  of photomultiplier tube  2  to generate and multiply photoelectrons in the same manner as the above. The amount of light made incident on photoelectric surface  71  is thus increased by the amount corresponding to the reflection at surface  77  at the other side of the dynode, thereby enabling detection of light caused by weak chemiluminescence.

TECHNICAL FIELD

This invention concerns a luminescent reaction measurement device, whichmakes a sample gas react with an oxidizing gas and thereby emitschemiluminescence and detects the light resulting from thisluminescence.

BACKGROUND ART

In recent years, there has been an increasing demand for concentrationmeasurement devices of the type, which makes nitrogen monoxide, etc., ina sample gas undergo a chemical reaction with ozone or other oxidizinggas and measures the concentration of the nitrogen monoxide, etc., inthe sample gas based on the intensity of the light due tochemiluminescence resulting from the reaction. With such a device, it ispossible, for example, to measure the concentration of nitrogen monoxidein the expired air of an asthmatic patient in order to monitor theeffects of treatment, and to measure the concentration of nitrogenmonoxide in the exhaust gas of an automobile in order to tackleenvironmental problems.

Such a concentration measurement device requires a luminescent reactionmeasurement device that measures the intensity of the light due tochemiluminescence, and a luminescent reaction measurement device, suchas that disclosed in Japanese Unexamined Patent Publication (Tokukai)No. Hei 7-333150, is popularly used. This device is equipped with areaction tank, having an indented part formed therein, and a photodiode,having a light receiving surface and serving as a light detector, andthis photodiode is fitted into the indented part of the reaction tank sothat a reaction chamber of a predetermined space is formed by the lightreceiving surface and the inner surface of the indented part of thereaction tank.

With this luminescent reaction measurement device, for example, nitrogenmonoxide is made to react with ozone in the reaction chamber, theintensity of the light resulting from chemiluminescence is detected bythe light receiving surface of the photodiode and an electrical signalaccording the detection is output.

DISCLOSURE OF THE INVENTION

Improvement of the detection sensitivity of luminescent reactionmeasurement devices is being desired recently to enable the detection ofmore dilute gases. However, with the prior-art luminescent reactionmeasurement device, the light detector forms a part of the wall of thereaction chamber and thus when the light detector is cooled to reducethe noise of the light detector, the temperature of the interior of thereaction chamber drops, thus causing the reaction rate of thechemiluminescence to drop and preventing improvement of the detectionsensitivity. Also, if the reaction chamber is made large to increase theamount of light due to chemiluminescence and this is detected by a largelight detector, the background noise increases as a result of making thelight detector large and furthermore, the heat generated by the lightdetector itself increases, making the cooling of the light detectordifficult and thus preventing improvement of the detection sensitivity.

This invention has been made to resolve the above problems and an objectthereof is to provide a luminescent reaction measurement device that canmeasure light due to chemiluminescence at high sensitivity by a simplearrangement.

This invention provides in a luminescent reaction measurement device,which makes a sample gas and an oxidizing gas react in a reactionchamber and detects, by means of a light detector, the intensity of thelight resulting from the chemiluminescence that occurs during thereaction, a luminescent reaction measurement device characterized inthat the reaction chamber is arranged with its inner surfaces beinglight reflecting and is equipped with a light transmitting window thatmakes the light due to the chemiluminescence in the reaction chamber beemitted towards the light detector that is installed outside theabovementioned reaction chamber, the light detector is a side-on typephotomultiplier tube, comprising a cylindrical container, into which theemitted light due to chemiluminescence enters from the peripheralsurface, a reflecting type photoelectric surface, photoelectricallyconverting the light due to chemiluminescence that enters inside theabovementioned container and generating photoelectrons, and a pluralityof dynodes, each having, on a surface at one side, a secondary electronemission surface that emits secondary electrons upon incidence ofelectrons and thereby successively multiplying and outputtingphotoelectrons, and at least a part of the dynodes receives, on thesurface at the other side, the light due to chemiluminescence thatenters from the peripheral surface and reflects the light toward thelight transmitting window of the reaction chamber.

With this invention's luminescent reaction measurement device, the lightresulting from chemiluminescence in the reaction chamber is transmittedthrough the light transmitting window and a large part of the light ismade incident on the photoelectric surface of the photomultiplier tubeto cause the generation of photoelectrons, and these photoelectrons areoutput upon being successively multiplied by the surfaces at one side ofthe dynodes. Meanwhile, a part of the light is made incident on thesurfaces at the other side of the dynodes without being made incident onthe photoelectric surface and this light is reflected by the surfaces atthe other side of the dynodes, returns to the reaction chamber via thelight transmitting window, is reflected furthermore by the lightreflecting surface inside the reaction chamber, emitted again from thelight transmitting window, made incident on the photoelectric surface ofthe photomultiplier tube, and photoelectrons are generated, multiplied,and output in like wise manner. The amount of light made incident on thephotoelectric surface is thus increased by the amount reflected by thesurfaces at the other side of the dynodes to enable the detection oflight caused by weak chemiluminescence.

Also, since the photomultiplier tube, which is the light detector, isseparated from the reaction chamber and the photomultiplier tube can becooled to reduce the noise generated in the photomultiplier tube withoutlowering the temperature of the interior of the reaction chamber, thedetection of weaker chemiluminescence is enabled.

Here, the surfaces at the other side of the dynodes that receive andreflect the light due to chemiluminescence are preferably formed ofgold.

The surfaces of the other side of the dynodes are thus made high inreflection efficiency and the amount of light returning to the reactionchamber is increased to enable the detection of light caused by weakchemiluminescence to be carried out more favorably.

Also, the dynode that receives and reflects the light due tochemiluminescence by the surface of the other side is preferably a firstdynode that first receives the photoelectrons generated by thephotoelectric surface. Reflection of light is thereby carried outfavorably.

Also, the photomultiplier tube is preferably equipped with a coolingdevice that cools the photoelectric surface. Cooling of thephotoelectric surface is thereby carried out efficiently for reductionof noise and detection of weak chemiluminescence is carried out evenmore favorably.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a general perspective view showing a luminescent reactionmeasurement device of an embodiment.

FIG. 2 is a sectional view of the reaction module in FIG. 1.

FIG. 3 is a side view partly in section of the luminescent reactionmeasurement device of FIG. 1.

FIG. 4 is a horizontal sectional view of the luminescent reactionmeasurement device of FIG. 1.

FIG. 5 is a front view of the luminescent reaction measurement device ofFIG. 1.

BEST MODE FOR CARRYING OUT THE INVENTION

A favorable embodiment of a luminescent reaction measurement device bythis invention will be described in detail with reference to theattached drawings. In the description using the drawings, the same orcorresponding elements shall be provided with the same symbol andredundant description shall be omitted.

FIG. 1 is a general perspective view showing a luminescent reactionmeasurement device of an embodiment. Luminescent reaction measurementdevice 1 of this embodiment measures the concentration of nitrogenmonoxide contained in a sample gas, and for this purpose, makes thenitrogen monoxide in the sample gas react with ozone, which serves as anoxidizing gas, to make chemiluminescence occur and measures theintensity of the light resulting from this luminescence.

Luminescent reaction measurement device 1 is equipped with a reactionmodule 20, which is equipped in turn with a reaction chamber 4 in whichthe nitrogen monoxide in the sample gas is made to react with ozone, anda light measurement module 21, onto which reaction module 20 isinstalled and which measures the intensity of the light of thechemiluminescence resulting from the reaction in reaction chamber 4 ofreaction module 20.

As shown in FIG. 2, reaction module 20 is equipped with a reaction cell5, having an indented part 63 formed therein, and a lid plate 6, whichserves as a lid for indented part 63 of reaction cell 5 and formsreaction chamber 4 by closing indented part 63.

Reaction cell 5 has an open rectangular tube part 35 formed so as toprotrude from a surface at one side (surface at the opposite side of lidplate 6) at the center of a rectangular plate of predeterminedthickness. At the end of rectangular tube part 35, a red filter (lighttransmitting window) 3, having the same outer diameter as rectangulartube part 35 and closing the abovementioned end, is adhered by means ofan adhesive agent 36. Indented part 63 is formed by red filter 3 and theinner walls of rectangular tube part 35.

Red filter 3 functions as a long-wavelength transmitting filter that issuitable for the spectrum of the chemiluminescence and emits diffuselight due to the chemiluminescence that occurs inside reaction chamber 4to the exterior (left side of the figure).

As adhesive agent 36, an adhesive agent, which by itself does not giverise to a gas that causes a luminescent reaction, does not extinguishthe luminescent reaction, and is not degraded by the oxidizing gas,etc., is favorable, and for example, a silicon adhesive agent may beused.

On the inner walls of rectangular tube part 35 is formed a gold platinglayer 40, which improves the light reflecting property and preventscorrosion due to the oxidizing gas.

Meanwhile, lid plate 6 is a rectangular plate of substantially the samesize as reaction cell 5, and at a part that covers indented part 63 ofreaction cell 5 and becomes a part of the inner walls of reactionchamber 4, a gold plating layer 41 is formed in the same manner as withthe inner walls of rectangular tube part 35 of reaction cell 5. Also ata surface of lid plate 6 that contacts reaction cell 5 at the outer sideof reaction chamber 4 a groove 37 for fixing an O-ring is formed in aring-like manner. Furthermore, at a central part of the rear surface oflid plate 6, a box-like protruding part 39 is formed, and in thisprotruding part 39 are formed four gas ports 27, 28, 29, and 30, whichrespectively put the interior of reaction chamber 4 in communicationwith the exterior.

As shown in FIG. 1, light measurement module 21 has a long, box-shapedcase 50, and this box-shaped case 50 is equipped with a side plate 50 aonto which reaction module 20 is installed. As shown in FIG. 3 and FIG.4, in the interior of case 50, a photomultiplier tube 2, which detectslight due to chemiluminescence from reaction chamber 4 of reactionmodule 20, is erected close to side plate 50 a.

This photomultiplier tube 2 shall now be described in detail.Photomultiplier tube 2 has a cylindrical glass bulb 75 and is equippedwith a main detector body 102 inside this glass bulb 75. Main detectorbody 102 mainly comprises a lattice electrode 70, through which lightcan be transmitted, a reflecting type photoelectric surface 71, whichgenerates photoelectrons by photoelectric conversion of the light due tochemiluminescence that is made incident upon being transmittedsuccessively through the peripheral surface of glass bulb 75 and latticeelectrode 70, a substrate 72, which holds this photoelectric surface 71on its surface, a plurality of stages of dynodes 78, each having asecondary electron emission surface 79, which emits secondary electronsupon incidence of electrons, formed on a surface at one side andsuccessively multiplying, at this surface at one side, thephotoelectrons that are emitted from photoelectric surface 71 and guidedby lattice electrode 70, an anode 80, which collects the multipliedphotoelectrons and takes them out as an output signal, and a pluralityof pin terminals 81 for applying high voltage successively acrossintervals between lattice electrode 70 and anode 80 as shown in FIG. 3.This photomultiplier tube 2 is a so-called side-on type photomultipliertube.

As shown in FIG. 4, of the dynodes 78 that comprise this photomultipliertube 2, a first dynode 78 a, onto which the photoelectrons generated atphotoelectric surface 71 are made incident first, is curved in a concavemanner with respect to photoelectric surface 71, the surface opposingphotoelectric surface 71 is made the secondary electron emission surface79, and the rear surface (surface at the other side) has a gold platinglayer (gold) 77 formed thereon.

Also as shown in FIG. 3, with photomultiplier tube 2, a metal conductiveplate 84 is installed so as to close the open end at the upper side ofglass bulb 75, a setting base 83 of good thermal conductivity is setabove conductive plate 84, a Peltier element (cooling device) 76, whichcools setting base 83 by the Peltier effect, is installed above settingbase 83, and radiating fins 86, which radiate the heat of Peltierelement 76, are equipped above Peltier element 76. On the roof plate ofcase 50 above radiating fins 86 is installed a cooling fan 59, whichcools the radiating fins 86. At the lower surface of conductive plate 84is equipped with a contact piece 82 of good thermal conductivity thatconnects conductive plate 84 with substrate 72 that holds photoelectricsurface 71.

Via substrate 72, contact piece 82, conductive plate 84, and settingbase 83, photoelectric surface 71 is cooled efficiently by Peltierelement 76, and photoelectric surface 71 is thus maintained adequatelyat a low temperature so that the generation of noise due to thermions isreduced and the sensitivity is improved. The energy required to coolphotoelectric surface 71 is also reduced and the waiting time forcooling is also shortened.

Since photoelectric surface 71 is cooled directly without cooling theentirety of photomultiplier tube 2, the temperature of the interior ofreaction chamber 4 is not lowered even if photomultiplier tube 2 andreaction chamber 4 are positioned close to each other, and sincephotomultiplier tube 2 and reaction chamber 4 can be positioned closerto each other, detection of luminescence at higher sensitivity isenabled.

Also as shown in FIG. 3 and FIG. 4, on side plate 50 a of lightmeasurement module 21, a rectangular tube part 51, which protrudestowards the inner side of case 50, is formed at a part opposing maindetector body 102 of photomultiplier tube 2 near the center of sideplate 50 a.

On the inner surface of this rectangular tube part 51 is equipped with arectangular-tube-shaped entry port 55, the inner diameter of which ismade the same as the outer diameter of rectangular tube part 35 ofreaction cell 5 of reaction module 20, and which guides the light due tochemiluminescence to photomultiplier tube 2, is formed by an insulatingmaterial and holds glass bulb 75.

Reaction module 20 is arranged by inserting red filter 3 and rectangulartube part 35 of reaction cell 5 in entry port 55 of light measurementmodule 21 and overlapping lid plate 6, having an O-ring 38 insertedinside groove 37 for sealing, onto the rear surface of reaction cell 5,and this reaction module 20 is fixed by bolts 58 onto side plate 50 a ofcase 50 of light measurement module 21.

Here, with photomultiplier tube 2, the installation angle in theperipheral direction is set as shown in FIG. 4 so that first dynode 78 adoes not block the path of light that is made incident on photoelectricsurface 71 from reaction chamber 4 and the curving part at the redfilter 3 side of gold plating layer 77 on the rear surface of firstdynode 78 opposes red filter 3, thereby enabling the light entering fromreaction chamber 4 to be received efficiently by photoelectric surface71 and enabling the light received by a part of the rear surface offirst dynode 78 a to be reflected efficiently towards red filter 3. Theangle α of photoelectric surface 71 with respect to the normal to sideplate 50 a is preferably set in the range of 61 to 66°, and in thiscase, photomultiplier tube 2 is positioned so that the line joining thepin of fourth dynode 78 b and the center of photomultiplier tube 2 isapproximately 90° with respect to the normal to side plate 50 a.

The inner diameter in the horizontal direction of rectangular tube part35 of reaction cell 5 (the inner diameter shown in FIG. 4) is set to awide diameter in order to enable adequate incidence of light fromreaction chamber 4 onto photoelectric surface 71 and a part of the rearsurface of first dynode 78 a, and for the same reason, the innerdiameter in the vertical direction (the inner diameter shown in FIG. 3)is set greater than or equal to the height of the effective area ofphotoelectric surface 71 and first dynode 78 a.

The protruding length (the length shown in FIG. 3 and FIG. 4) ofrectangular tube part 35 is set so that in the state in whichrectangular tube part 35 is mounted inside entry port 55, the outersurface of red filter 3 is positioned close to glass bulb 75 ofphotomultiplier tube 2. By thus bringing reaction chamber 4 andphotomultiplier tube 2 close to each other, the light due tochemiluminescence, which arises inside reaction chamber 4 and becomesdiffuse light, is restrained from attenuating due to diffusion, etc.,along the optical path and is made incident efficiently ontophotomultiplier tube 2.

Red filter 3 is fixed onto reaction cell 5 using adhesive agent 36, andthus in comparison to a case where red filter 3 is fixed by a bolt andan O-ring, etc., the securing of space, etc., for the strutting of abolt and for a groove for an O-ring is made unnecessary. Photomultipliertube 2 and red filter 3 can thus be positioned close to each other andthe diffusion of light is restrained to improve the efficiency ofconvergence and the sensitivity. Experiments by the present inventorhave shown that in comparison to cases where red filter 3 is installedusing an O-ring and a bolt, etc., without use of adhesive agent 36,luminescent reaction measurement device 1 of the present embodiment isincreased by 60% or more in signal amount.

As shown in FIG. 5, gas ports 27 to 30 are connected respectively to anitrogen monoxide introduction tube 7 for introducing sample gas,containing nitrogen monoxide gas, into reaction chamber 4, an ozoneintroduction tube 8 for introducing ozone into reaction chamber 4, a gasexhaust tube 9 for exhausting the gas after reaction inside reactionchamber 4, and a pressure measurement tube 10 for detection of thepressure inside reaction chamber 4.

As shown in FIG. 1, ozone introduction tube 8 is connected to an ozonegenerating device 12, gas exhaust tube 9 is connected via a flowregulating valve 15 to a suction pump 13, and pressure measurement tube10 is connected to a pressure sensor 14. Since the exhaust gas exhaustedfrom gas exhaust tube 9 may be hazardous to the human body in somecases, it is detoxified by being passed through an activated carboncolumn, etc., and thereafter released to the atmosphere.

Luminescent reaction measurement device 1 of the present embodiment isarranged as described above. The actions of luminescent reactionmeasurement device 1 shall now be described. Here, the actions in a casewhere luminescent reaction measurement device 1 is applied as a devicefor measuring the concentration of nitrogen monoxide in the expired airof an asthmatic patient shall be described.

First, voltage is applied to main detection body 102 of photomultipliertube 2 to set up a state in which detection of light is enabled andPeltier element 76 and cooling fan 59 are driven to cool photoelectricsurface 71 of photomultiplier tube 2. Ozone from ozone generating device12 is then introduced via ozone introduction tube 8 into reactionchamber 4 and a patient's expired air that contains nitrogen monoxide isintroduced into reaction chamber 4 via nitrogen monoxide introductiontube 7.

At this point, in reaction chamber 4, the nitrogen monoxide in theexpired air and the ozone undergo the chemical reaction expressed by thefollowing formula and cause chemiluminescence. Here, NO₂* indicatesnitrogen dioxide in an excited state.NO+O₃→NO₂*+O₂NO₂*→NO₂+hν

The light due to this chemiluminescence is then transmitted through redfilter 3 and emitted towards photomultiplier tube 2 directly or afterbeing reflected by gold plating layers 40 and 41 on the wall faces ofreaction chamber 4. Suction pump 13 is activated to continuously exhaustthe gas resulting from this reaction out of the system via gas exhausttube 9. In this process, flow regulating valve 15 is operated to adjustthe exhaust rate so that the amount of light emitted in reaction chamber4 is maximized.

At this point, a large part of the light that enters photomultipliertube 2 is made directly incident on photoelectric surface 71. Theincident light then undergoes photoelectric conversion at photoelectricsurface 71 to become photoelectrons, and these photoelectrons are madeincident on the secondary electron emission surface 79 side of thesurface of first dynode 78 a and multiplied in the form of emission ofsecondary electrons, which are furthermore multiplied successively byother dynodes 78 and then collected as an output signal at anode 80,thereby providing an output that is in accordance to the luminousintensity.

Meanwhile, the light that is not made directly incident on photoelectricsurface 71 is made incident on a part of gold plating layer 77 at therear surface of first dynode 78 a, is reflected by this gold platinglayer 77, transmitted through red filter 3, and returned back intoreaction chamber 4. The light that is returned inside reaction chamber 4is then reflected by gold plating layers 40 and 41 of the inner wallsinside reaction chamber 4, transmitted through red filter 3, and madeincident on photoelectric surface 71 of photomultiplier tube 2, and thegeneration and multiplication of photoelectrons are carried out toprovide an output in the same manner as described above.

The light amount of the light due to chemiluminescence that is madeincident on photoelectric surface 71 of photomultiplier tube 2 is thusincreased by the amount reflected by part of gold plating layer 77 atthe rear surface of first dynode 78 a, thereby improving the sensitivityand enabling the detection of light due to weak chemiluminescence.

Also, since photomultiplier tube 2 and reaction chamber 4 are separatedand reaction chamber 4 is thus not cooled when photomultiplier tube 2 iscooled so that the luminescent reaction is not inhibited, the light dueto a luminescent reaction can be measured at higher sensitivity.

Gold plating layer 77 on the rear surface of first dynode 78 a is highin reflection efficiency so that the loss due to reflection of the lightthat is reflected by first dynode 78 a and returns to red filter 3 islow, thus further improving the detection sensitivity.

The data on the intensity of the chemiluminescence light thus obtainedby means of photomultiplier tube 2 are analyzed by an external computingdevice, etc. (not illustrated) to measure the concentration of nitrogenmonoxide based on the intensity of chemiluminescence. Here, theintensity of the light due to chemiluminescence is in a proportionalrelationship with the nitrogen monoxide concentration if the amount ofozone in reaction chamber 4 is adequate, and the nitrogen monoxideconcentration can thus be determined by measuring the intensity of thelight.

This invention's luminescent reaction device/measurement device is notlimited to the embodiment described above.

For example, the luminescent reaction measured with luminescent reactionmeasurement device 1 is not limited to a reaction of nitrogen monoxideand ozone. For example, besides nitrogen monoxide, ethylene, isoprene,ammonia, or formaldehyde (formalin), etc., which reacts with ozone togive rise to luminescence, may be used as the gas in the sample gas thatis subject to concentration measurement. Also, besides ozone, fluorine,chlorine, etc., may be used as the oxidizing gas.

Also, though with the present embodiment, light due to chemiluminescenceis reflected by a part of the rear surface of first dynode 78 a, thisinvention is not limited thereto and the light may be reflected byanother dynode, such as a ninth dynode.

Also, though with the present embodiment, gold plating layer 77 isformed on the rear surface of first dynode 78 a to provide a high lightreflecting property, this invention is not limited thereto as long asthe reflectance of the light due to chemiluminescence is adequatelyhigh, and for example, plating of another noble metal may be used, anddepending on the light due to chemiluminescence, the base material ofnickel, etc., may be used as it is without plating. The same applies togold plating layers 40 and 41 of the inner walls inside reaction chamber4 of reaction module 20, and as long as corrosion resistance is providedand the light reflectance is high, a plating of another metal may beused in the same manner, or a member of solid noble metal, etc., may bemirror polished, etc.

Also, though with the present embodiment, red filter 3 is employed asthe light transmitting window, this invention is not limited thereto,and another filter or glass plate, etc., may be used as long as ittransmits the light due to chemiluminescence.

Also, though with the present embodiment, Peltier element 76 is equippedas the cooling device and photomultiplier tube 2, in which justphotoelectric surface 71 can be cooled efficiently is employed, thisinvention is not limited thereto, and a side-on type photomultipliertube and a cooling device that cools the entirety of thisphotomultiplier tube may be employed, and even in this case, sincephotomultiplier tube 2 and reaction chamber 4 are separated, reactionchamber 4 will not be cooled and the lowering of the chemiluminescentreaction rate will not occur. Also, in a case where the amount of heatgenerated by a photomultiplier tube is low, etc., a cooling device doesnot have to be equipped.

INDUSTRIAL APPLICABILITY

This invention can be applied to the concentration measurement ofnitrogen monoxide or other component in a sample gas.

1. A luminescent reaction measurement device, which makes a sample gasand an oxidizing gas react in a reaction chamber and detects, by meansof a light detector, the intensity of the light resulting from thechemiluminescence that occurs during said reaction, wherein innersurfaces of said reaction chamber are arranged to be light reflecting,and said reaction chamber is equipped with a light transmitting windowthat makes said light due to chemiluminescence in said reaction chamberbe emitted therefrom towards said light detector that is installedoutside said reaction chamber, said light detector is a side-on typephotomultiplier tube, comprising a cylindrical container, into whichemitted light due to chemiluminescence enters through a peripheralsurface, a reflecting type photoelectric surface for photoelectricallyconverting said light due to chemiluminescence that has entered insidesaid container and generating photoelectrons, and plurality of dynodes,each having, on a surface at one side, a secondary electron emissionsurface that emits secondary electrons upon incidence of electrons andthereby successively multiplying and outputting said photoelectrons, andat least one of said dynodes receives, on a surface at a second side,said light due to chemiluminescence that has entered through saidperipheral surface and reflects it toward said light transmitting windowof said reaction chamber.
 2. The luminescent reaction measurement deviceas set forth in claim 1, wherein the surface at the second side of thedynode that receives and reflects said light due to chemilumiescence isformed of gold.
 3. The luminescent reaction measurement device as setforth in claim 1, wherein the dynode that receives and reflects saidlight due to chemiluminescence by the surface of the second side is afirst dynode that first receives the photoelectrons generated by saidphotoelectric surface.
 4. The luminescent reaction measurement device asset forth in claim 2, wherein the dynode that receives and reflects saidlight due to chemiluminescence by the surface of the second side is afirst dynode that first receives the photoelectrons generated by saidphotoelectric surface.
 5. The luminescent reaction measurement device asset forth in claim 1, wherein said photomultiplier tube is equipped witha cooling device that cools said photoelectric surface.
 6. Theluminescent reaction measurement device as set forth in claim 2 whereinsaid photomultiplier tube is equipped with a cooling device that coolssaid photoelectric surface.
 7. The luminescent reaction measurementdevice as set forth in claim 3 wherein said photomultiplier tube isequipped with a cooling device that cools said photoelectric surface. 8.The luminescent reaction measurement device as set forth in claim 4wherein said photomultiplier tube is equipped with a cooling device thatcools said photoelectric surface.